Process for preparing scented cellulosics

ABSTRACT

The present invention provides a process for optimizing the fragrance of a scented cellulosic.

This application claims the benefit of U.S. Provisional Application No.60/739,304, filed Nov. 23, 2005, U.S. Provisional Application No.60/705,807, filed Aug. 4, 2005, and U.S. Provisional Application No.60/692,644, filed Jun. 20, 2005. Each of these applications are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

The present application provides scented cellulosics that can be usedfor various end-use applications including, personal accessories,scented point-of-purchase applications, and promotional items for finefragrances.

BACKGROUND OF THE INVENTION

Various applications that employ plastics (e.g., cellulosics) could beenhanced if the plastics could exude a pleasing or appropriate fragrancebased on their end use.

U.S. Pat. No. 5,460,787 discloses a scented card which includes afragranced thermoplastic material. The process of producing the scentedcard includes, providing a dry particulate thermoplastic material,blending a chemical flowing agent and at least one fragrance into thethermoplastic material to form a mixture, and heating the mixture in athermoplastic extruder. The chemical flowing agent creates gas pocketswithin which the fragrance is trapped.

U.S. Pat. No. 3,661,838 discloses a scented plastic composition having aporous, finely divided silica powder having absorbed thereon a liquidscent emitting substance that is contained within the plastic material.The patent states that previous attempts have been made to dissolve aliquid scent-emitting substance into the liquid plasticizer, and amixture of the scent emitting substance and plasticizer is subsequentlyadded to the resin followed by heating and solidification. According tothe patent, the liquid scent emitting substances which are dissolved inthe plasticizers under known processes evaporate or decompose due to theprocessing heat applied during the time of the heat melting process, anddo not provide sufficient fragrance intensity.

U.S. Published Patent Application No. 2003/0072733 discloses celluloseacetates as absorbent materials in a process for absorbing moistureand/or malodor in providing a fragrance to the surrounding ambience. Thecellulose acetate and cellulose butyrate is not plasticized nor is aprocess provided for providing a fragrance plastic product.

U.S. Pat. No. 6,703,012 discloses compositions containing fragrances andpowdered water-soluble polymers that are processed into toilet blocks.Polyvinyl acetates and mixtures of polyvinyl alcohol in partiallyhydrolyzed polyvinyl acetate are used. The fragrance is introduced intothe extruder and the time of extruding the polymer.

U.S. Pat. No. 4,492,644 discloses and ethylene and vinyl acetatecopolymer used with a perfume. The ethylene-vinyl acetate copolymer ispre-formed into granules having a diameter of about one to tenmillimeters. A perfume and granulated copolymer are mixed at atemperature in a range of about ten degrees Celsius. This patent statesthat the granulated ethylene-vinyl acetate copolymer containing theperfume may increase in volume according to the amount of the perfumeimpregnated and absorbed therein, but it will never exhibit a softeningeffect. The '644 patent is not directed to cellulose acetate esters,such as cellulose acetate, cellulose acetate butyrate, and celluloseacetate propionate.

U.S. Pat. No. 4,598,006 discloses a method for impregnating athermoplastic polymer with a fragrance by dissolving the fragrance in avolatile swelling agent maintained at or near super-critical conditionsfor the volatile swelling agent, swelling the thermoplastic polymer bycontacting it at or near the supercritical conditions of the volatileswelling agent, then reducing the pressure so that the volatile swellingagent diffuses out of the thus impregnated thermo-plastic polymer. Thethermoplastic polymer swells upon contact with the fragrance at or nearsupercritical conditions. The contacting permits rapid diffusion of theimpregnation material into the polymer. Swelling agents include carbondioxide, ethylene and nitrous oxide.

There is a need for imparting fragrance to cellulosics, includingcellulose acetate, cellulose acetate butyrate, and cellulose acetatepropionate, that has sufficient fragrance intensity while minimizing theamount of fragrance used, and also avoids compromising the plastic bythe addition of silica materials or the addition of extraneouscomponents to create formation voids within the plastic. There is afurther need to optimize the fragrance of a cellulosic either by processimprovements or additives so that end-use products that are made of thefragranced cellulosic have an optimal fragrance amount and are appealingto the consumer.

BRIEF SUMMARY OF INVENTION

The present application provides a process for preparing scentedcellulosic with optimal fragrance intensity, including the steps ofdetermining an amount of net plasticizer to be added to a pre-meltcellulosic composition; selecting a high preliminaryfragrance:plasticizer weight ratio of the net plasticizer; adding thenet plasticizer with the high preliminary fragrance:plasticizer ratio;determining the fragrance:plasticizer weight ratio of net plasticizerthat achieves maximum fragrance intensity in the processed scentedcellulosic by decreasing the fragrance:plasticizer ratio of the netplasticizer in iterative trials; and selecting a finalfragrance:plasticizer ratio based on the desired fragrance intensity ofthe scented cellulosic, whereby the final fragrance:plasticizer ratio isless than or equal to the fragrance:plasticizer ratio that achieves themaximum fragrance intensity.

The present invention also provides a scented cellulosic compositioncomprising a cellulosic, a plasticizer, a fragrance component, and asolvent system that comprises a component that has both a non-polar andpolar character. In one embodiment, the solvent system comprises, orconsists essentially of, a glycol or a glycol ether, such as but notlimited to, hexylene glycol, propylene glycol, butyl carbitol,2-butoxyethanol (ethylene glycol mono-n-butyl ether) or pentyl ethyleneglycol. In a preferred embodiment, the solvent system comprises hexyleneglycol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual drawing of the fragrance profile of a scentedcellulosic having varying weight ratios of fragrance:plasticizer.

DETAILED DESCRIPTION Definitions

As used herein and in the appended claims, the singular forms “a,” “an,”and “the,” include plural referents unless the context clearly indicatesotherwise. Thus, for example, reference to “a plasticizer” includes oneor more of such plasticizers, and reference to “the method” includesreference to equivalent steps and methods known to those of ordinaryskill in the art that could be modified or substituted for the methodsdescribed herein.

The term “cellulosic”, as used herein, refers to cellulose acetates andcellulose acetate esters and includes, but is not limited to, celluloseacetate, cellulose acetate propionate, and cellulose acetate butyrate.Cellulose acetate esters include, but are not limited to, cellulosediacetate and cellulose triacetates. The term “cellulosic” also includesall hydrates of cellulosics (e.g. anhydrous cellulose acetate, celluloseacetate monohydrate, cellulose acetate dihydrate, cellulose acetatetrihydrate, and cellulose acetate tetrahydrate) as well as anhydrousforms of cellulosics.

The term “optimal fragrance intensity”, as used herein, refers to afragrance intensity of scented cellulosic which is obtained using aminimum amount of fragrance for the given fragrance intensity. Forexample, each point of the Odor Intensity-Fragrance loading curve shownin FIG. 1 that is to the left of Point C (including Point C itself) isan optimal fragrance intensity. In contrast, point B in FIG. 1 is not anoptimal fragrance intensity, even though it has the same odor intensityas point A (which is an optimal fragrance intensity), since it is notobtained with a minimum amount of fragrance. If the intensity of theemitted fragrance decreases upon selecting a lower fragrance:plasticizerratio, then the scented cellulosic has an optimal fragrance intensity.Under these circumstances, the ratio of fragrance:plasticizer can beincreased until a fragrance:plasticizer weight ratio is obtained thatachieves the maximum fragrance intensity in the scented cellulosic. Forpurposes of this application, a scented cellulosic with optimalfragrance intensity also has an amount of fragrance that yields anoptional fragrance longevity since both intensity and longevity arefunctions of the diffusion of the fragrance through the cellulosic.

The term “pre-melt cellulosic”, as used herein, refers to theunprocessed cellulosic starting material that is to be mixed with aplasticizer and processed with one or more extrusion or processingtechniques. The pre-melt cellulosic is provided in solid powdered formwith uniform particle distribution, as opposed to a liquid or gel. Inpreferred embodiments, the pre-melt cellulosic is processed to providefragranced cellulosics for end-use applications, particularly end-useapplications with structural form.

The term “maximum fragrance intensity” as used herein refers to themaximum odor intensity possible for a cellulosic. The maximum fragranceintensity of FIG. 1 is point C.

The term “net plasticizer” refers to all components having aplasticizing effect on cellulosics, and generally refers to the effectof the plasticizer (as that term is traditionally used) plus thefragrance composition, plus the solvent composition.

A “high preliminary fragrance:plasticizer weight ratio” is a weightratio of fragrance:plasticizer that provides a fragrance intensity doesnot provide optimal fragrance intensity per unit of fragrance present inthe cellulosic. A person of ordinary skill will know that a highpreliminary fragrance:plasticizer weight ratio is selected when, uponrunning a second trial with a lower fragrance:plasticizer weight ratio(e.g., a scented cellulosic with a decreased amount of fragrance), theintensity of the emitted fragrance increases. The term “plasticizer” inthe fragrance:plasticizer ratio refers to the weight of traditionalplasticizer in the pre-melt cellulosic, and the term fragrance refers tothe weight of fragrance in the pre-melt cellulosic.

A “low preliminary fragrance:plasticizer weight ratio” is a weight ratioof fragrance:plasticizer that provides a fragrance intensity that fallsbelow the maximum possible fragrance intensity of a given cellulosicwhile maximizing the intensity that is achieved per unit of fragrancepresent in the cellulosic. A person of ordinary skill will know that alow preliminary fragrance:plasticizer weight ratio is selected when,upon running a second trial with a higher fragrance:plasticizer weightratio (e.g., a scented cellulosic with an increased amount offragrance), the intensity of the emitted fragrance increases. The term“plasticizer” in the fragrance:plasticizer ratio refers to the weight oftraditional plasticizer in the pre-melt cellulosic, and the termfragrance refers to the weight of fragrance in the pre-melt cellulosic.

The term “solvent system” refers to solvents containing a component thatpossesses both a non-polar entity, such as, but not limited to, anon-polar alkylene chain, and a polar entity such that the component hasboth a non-polar and polar character. Examples of polar entities withinmolecules that are included in the solvent system include alcohol,hydroxyl, carboxyl (including carboxyl groups found in organic acids),ester, halogen and primary, secondary and tertiary amine functionalgroups.

As used herein, the term “soluble” refers to a condition in which amaterial is dissolved, or substantially dissolved in the given solvent,i.e. the material breaks up into particles (generally single atoms ormolecules) that are too small to be seen with the naked eye. Liquidmaterials are said to be solvent in liquid solvents when the liquidmaterial and liquid solvent combine to form a solution such that the twocomponents are completely miscible or substantially miscible to thenaked eye (e.g. including solvents in which the liquid solute formsmicrocolloids such that the two components appear completely orsubstantially miscible to the naked eye).

Reference to compounds used herein, including all glycols and glycolethers described in this application, includes polymers in which thereferenced compound forms a subunit. For example, reference to hexyleneglycol includes polymers in which hexylene glycol is a monomer in thepolymer chain.

As used herein, the term “about” means within 10% of a given value,preferably within 5%, and more preferably within 1% of a given value.Alternatively, the term “about” means that a value can fall within ascientifically acceptable error range for that type of value, which willdepend on how precise a measurement can be obtained by the availabletools.

All ratios and percentages are given as weight percent or weight ratiosunless otherwise noted.

Obtaining Optimal Fragrance Intensity and Longevity

The present application is based, in part, on the discovery thatfragranced cellulose acetates and cellulose acetate esters can exudeincreased fragrance intensity by carefully selecting thefragrance:plasticizer ratio. Surprisingly, it has been found thatcellulosics loaded with lower amounts of fragrance oftentimes exhibitmore intense fragrance emissions than the same cellulosic loaded withmore fragrance. In other words, a fragranced cellulose acetate orcellulose acetate ester having a lower fragrance:plasticizer ratio oftenhas a more intense fragrance emission, after processing, than thecounterpart cellulose acetate or cellulose acetate ester with a higherfragrance:plasticizer ratio. It is unexpected that after reaching amaximum odor intensity, the intensity of the cellulosic's fragrancebegins to decrease or stabilize as more fragrance is added to thecomposition.

A concept of the present invention is shown in FIG. 1, which is aprophetic fragrance intensity curve at increasing loading of fragrance.As the loading of fragrance increases, the fragrance intensity increasesto a certain point C. Thereafter, the intensity of the fragrancedecreases as more fragrance is loaded into the cellulosic.

Points A and B demonstrate a paradox of the present invention. Thefragrance weight percent corresponding to point A provides the same odorintensity as the fragrance weight percent corresponding to point B. Itis believed that, without benefit of the present invention, most wouldoperate in the region of this curve to the right of point C, in whichthe “return” per unit of fragrance—the most expensive component ofscented cellulosics—is not maximized. Without benefit of the presentinvention, persons of ordinary skill in the art would assume thatincreased fragrance loading necessarily provides a cellulosic withincreased fragrance intensity. Accordingly, without benefit of thepresent invention persons of ordinary skill would not select fragranceamounts that are less than or equal to the amount of fragrance thatachieves the maximum fragrance intensity (which corresponds to the wt %at point C in FIG. 1), therefore would not optimize the amount offragrance in the pre-melt cellulosic.

Correlations for diffusion coefficients factor in the “associationparameter” of the solvent (see C. R. Wilke, Chem. Eng. Prog., 45:218-224(1949)) and the “mobility” of the diffusing particle (seeNernst-Einstein equation described in F. Daniels and R. A. Alberty,Physical Chemistry, Wiley, New York, p. 650 (1955)). Chapter 16 ofTransport Phenomena, Bird, Stewart, and Lightfoot (1960) and theabove-mentioned technical journals are hereby incorporated by reference.Without being bound to any particular theory, it is believed that thereis an optimal ratio of fragrance: plasticizer for a givenplasticizer/fragrance combination. When the optimal fragrance:plasticizer ratio is exceeded, it is believed that the associationparameter of the solvent changes such that the diffusion of thefragrance through the cellulosic is hindered.

On a more physical level, it is believed that optimizedfragrance:plasticizer ratios, and hence, optimized levels of traditionalplasticizer better facilitate the formation of channels, continuousvoids, or a network of holes, within the processed cellulosic whichfacilitates the diffusion of the fragrance through the cellulosic.Increased diffusion through the cellulosic facilitates both increasedfragrance intensities and increased longevity of the fragrance. In otherwords, fragrance longevity and fragrance intensity are both a functionof the diffusion of fragrance through the cellulosic. Furthermore, inembodiments of the invention that include a solvent system that includesa component that has both a polar or non-polar character (discussedbelow) the diffusion of the fragrance through the cellulosic is furtherincreased since the fragrance is better distributed throughout thecellulosic and not accumulated into globules.

Also, it has been found that particular plasticizers, including thosespecifically set forth herein, better facilitate the diffusion, andhence delivery, of fragrance to the ambient atmosphere. Also, pigments,such as opaque color additives like Titanium Dioxide, hinder thediffusion of fragrance through the cellulosic.

Plasticizer and the “Net Plasticizer” Effect

The present invention is also based, in part, on the discovery that aportion of the fragrance, up to and including its entire weight mass,must be considered as an equivalent mass of plasticizer. Similarly, thepresent invention is also based, in part, on the discovery that aportion of additives including glycols and ethers of glycols describedbelow, up to and including its entire weight mass, must be considered asan equivalent mass of plasticizer. This is because the fragrances andadditives have a plasticizing effect in cellulosics in and bythemselves. The effect of the plasticizer plus the fragrance and otheradditives is referred to herein as the net plasticizer effect.

When a person of ordinary skill has determined the amount of plasticizerthat will achieve necessary processing parameters in a non-scentedcellulosic, one cannot merely add fragrance to this amount ofplasticizer and still obtain the same processing parameters.Accordingly, when determining the amount of plasticizer to be added inorder to achieve necessary processing parameters, one must account forthe plasticizing effect of the added fragrance and additive, such asalkylene glycol and glycol ether. While a certain level of traditionalplasticizer is always required to prevent degradation of the pre-meltcellulosic, the addition of fragrance and, for example, glycol or glycolether additives should be counteracted with a reduction in the amount oftraditional plasticizer employed in the scented cellulosic. Conversely,an increase in the amount of traditional plasticizer should becounteracted by a decrease in the amount of fragrance. The presentinvention is based, in part, on the surprising discovery that areduction in the amount of fragrance and increase in the amount oftraditional plasticizer in the pre-melt cellulosic oftentimes yieldsprocessed cellulosics with higher fragrance intensities and increasedfragrance longevity.

Therefore, in increasing the amount of fragrance which will yieldoptimal fragrance intensities, the amount of plasticizer should bedecreased in order to obtain similar processing characteristics.Conversely, when decreasing the amount of fragrance, the amount ofplasticizer should be increased. In many embodiments of the presentinvention, an increase or decrease of 1 unit of fragrance is effectivelycounteracted by a decrease or increase, respectively, of 1 unit ofplasticizer (see, e.g., Example 1 below).

The amount of net plasticizer will vary depending on the particular setof physical properties desired, and the particular cellulosic employed.Typical formulations of scented cellulose acetate butyrate may have, forexample, between about 4% and 23%, by weight, of net plasticizer.Typical formulations of scented cellulose acetate propionate may have,for example, between about 7% and 18%, by weight, of net plasticizer.Typical formulations of scented cellulose acetate may have, for example,between about 13% and 35%, by weight, of net plasticizer. Generally, theamount of net plasticizer is from about 20 wt % to about 40 wt % (e.g.,about 30 wt %).

For example, in one embodiment in which the cellulosic is celluloseacetate propionate, the plasticizer is dioctyl adipate (DOA) and ahexylene glycol additive is included, the amount of net plasticizer(DOA+fragrance+hexylene glycol) is from about 20 wt % to about 40 wt %,e.g., about 30 wt %. In a further illustration of this embodiment, theamount of traditional plasticizer is from about 2 wt % to about 35 wt %,or from about 4 wt % to about 35 wt %.

In an alternative embodiment, the cellulosic is cellulose acetate, theplasticizer is diethyl phthalate (DEP), the amount of net plasticizer isalso in the range of about 20 wt % to about 40 wt % (e.g., about 30 wt%). In a further aspect of this embodiment, the amount of traditionalplasticizer is from about 7 wt % to about 35 wt %, or from about 11 wt %to about 35 wt %.

Examples of plasticizers that can be used in various embodiments of thepresent invention include, but are not limited to, dibutyl phalate,diethyl phthalate, dimethyl phthalate, triacetin,diethylhexyl-phthalate, and dioctyl phthalate. Also, environmentallysensitive plasticizers can be used, such as plasticizers based on castoroil. These environmentally sensitive plasticizers can be used, forexample, as substitutes for phthalate plasticizers. Other plasticizerswill present themselves to those of ordinary skill in the art, includingthose set forth under “Plasticizers” in Volume 19 of the Encyclopedia ofChemical Terminology (4th edition) by Kirk-Othmer, which is herebyincorporated by reference.

Solvent Systems for Plasticizer/Fragrance Components

Components possessing both a non-polar entity and a polar entity areused in solvents to improve the dispersability of the fragrance in thepre-melt cellulosic. In such embodiments, combining the fragrance andthe plasticizer with the non-polar/polar solvent system facilitates themigration of the fragrance through the processed cellulosic. Sinceplasticizers fill the space between polymer strands, the plasticizersform a network of microscopic liquid filled channels throughout and onthe surface of the plastic which allows the fragrance to travel and toleach out of the plastic over time. If the fragrance is better dispersedthroughout the cellulosic matrix, i.e. not agglomerated into globuleswhich remain encapsulated in the cellulosic, their migration through thematrix over time is facilitated when processed with a solvent system ofthe present invention.

Generally, solvent systems which are soluble in both a) an alcohol(polar), e.g. ethanol, and b) benzene (non-polar) are included withinthe solvent systems in embodiments of the present invention. Someexamples of solvent systems are solvent systems comprising propyleneglycol, hexylene glycol, butyl carbitol and butyl ethylene glycol.Preferably, the solvent systems consists essentially of the componentthat has a non-polar entity and a polar entity, including solventsystems which consist essentially of a glycol, or a glycol ether,generically, or as described in greater detail below. Accordingly, thesolvent system have nonionic characteristics allowing them miscibilityin non-polar components (in this case the plasticizer) and availablefunctional (e.g. hydroxyl) groups allowing for hydrogen-bonding withmore polar materials (fragrance materials).

While not being bound to any particular theory, it is believed that theaddition of this class of solvents possessing non-polar character andavailable functional groups (e.g. hydroxyl groups) allows for greaterlong-term migration of fragrance materials via a mechanism in which thefragrance becomes attached (e.g. hydrogen bonded) to the plasticizer.Without the addition of this class of solvents, the plasticizer andfragrance will repel each other much like oil and water, causing themajority of the fragrance to be entrapped/encapsulated in the polymer.With the addition of this class of solvents the plasticizer and thefragrance become effectively one material encompassing a much largerpercentage of the overall plastic than just the fragrance alone.

Glycols

In one embodiment of the present invention, a glycol is included in apre-melt composition for a scented cellulosic, along with a plasticizerand a fragrance component. In one application of this embodiment, thepre-melt composition comprises an alkylene glycol. The glycol may be aC₃-C₁₂ substituted or unsubstituted alkylene glycol, a C₄-C₁₀substituted or unsubstituted alkylene glycol, a C₅-C₇ substituted orunsubstituted alkylene glycol. Other examples of alkylene glycols inembodiments of the present invention include methylene glycol, ethyleneglycol, propylene glycol, butylene glycol, pentylene glycol, hexyleneglycol, heptylene glycol, octlylene glycol, nonylene glycol, decyleneglycol, undecylene glycol, and dodecylene glycol.

In a preferred embodiment, the solvent system comprises, or morepreferably, consists essentially of, hexylene glycol. CAS reports thathexylene glycol is a water-white viscous liquid which exhibits slighthydroscopic properties. It is compatible with aromatic hydrocarbons andis miscible with water, fatty acids and low molecular weight alcohols.

Ethers of Glycols

In another embodiment of the present invention, a glycol ether isincluded in a pre-melt composition for a scented cellulosic, along witha plasticizer and a fragrance component. In one application of thisembodiment, the glycol ether is an alkyl ether of alkylene glycol(ethers of alkylene glycol). For example, in embodiments of the presentinvention, the glycol ether is a C₁-C₁₀, or a C₂-C₈, or a C₃-C₈ mono orpoly alkyl ether of an alkylene glycol. In a preferred embodiment, thesolvent system includes, or consists essentially of, monoethyl andmonobutyl ethers of diethylene glycol (e.g. butyl carbitol).

In one embodiment, the alkyl glycol ether is a monoethyl ether, e.g.n-ethyl ether, of an alkylene glycol. In one embodiment, the glycolether is a pentyl ether of an alkylene glycol, e.g. pentyl ethyleneglycol. In another embodiment, the glycol ether is a monobutyl ether,e.g. n-butyl ether of an alkylene glycol (e.g. ethylene glycol). In apreferred embodiment, the alkylene glycol is ethylene glycol, and theether is n-butyl.

In another embodiment, the alkyl glycol ether is selected from propyleneglycol monomethyl ether, dipropylene glycol monomethyl ether andtripropylene glycol monomethyl ether. These alkyl glycol ethers areavailable from Dow Chemicals under the tradenames Dowanol® PM, Dowanol®DPM, and Dowanol® TPM, respectively. In a preferred embodiment, thesolvent system includes, or consists essentially of, dipropylene glycolmonomethyl ether.

Effective Amounts of Glycol and Glycol Ether, Traditional Plasticizer,and Cellulosic in Pre-Melt Cellulosic

The amount of glycol or glycol ether used in embodiments of the presentinvention is an amount of glycol or glycol ether that is effective tofacilitate the migration of fragrance through the cellulosic. In oneembodiment of the present invention, the amount of glycol or glycolether ranges from about 0.1% to about 33% in the pre-melt composition.In another embodiment, the amount of glycol or glycol ether ranges fromabout 0.5% to about 20% in the pre-melt composition. In anotherembodiment, the amount of glycol or glycol ether ranges from about 1% toabout 11% in the pre-melt composition. In another embodiment, the amountof glycol or glycol ether ranges about 8% in the pre-melt cellulosic.These amounts of glycol or glycol ether are in weight percent, based onthe total weight of the pre-melt cellulosic.

In one embodiment of the present invention, the amount of cellulosicranges from about 48 wt %-93 wt %, the amount of glycol or glycol etherranges from about 0 wt % to about 12 wt %, the amount of fragranceranges from about 1% to about 30%, and the amount of traditionalplasticizer ranges from about 2 wt % to about 35 wt %. In an alternativeembodiment, the amount of cellulosic ranges from about 60 wt % to about80 wt %, the amount of glycol or glycol ether ranges from about 3% toabout 10 wt %, the amount of fragrance ranges from about 10 wt % toabout 25 wt % and the amount of traditional plasticizer ranges fromabout 10 wt % to about 25 wt %. It is imperative that the pre-meltcomposition contain enough cellulosic such that the pre-melt compositionis in powder from, as opposed to a gel or liquid. Therefore, the minimumamount of cellulosic contained in the pre-melt composition is generallyat least about 40 wt % of the total weight of the pre-melt cellulosic,or in another embodiment, above about 48 wt % of the total weight of thepre-melt cellulosic.

Modification of Net Plasticizer Amount

Higher net plasticizer amounts should be selected for projects whichrequire a softer melt flow upon processing the cellulosic. For example,for an end use applications such as a thin film for packaging, theamount of net plasticizer can be around 25%; whereas for a decorativemask end use that is desired to be softer, the amount of net plasticizercan be around 40%. Depending on the desired fragrance intensity of theend use product, the relative amount of fragrance is selected so as toprovide a scented cellulosic with optimal fragrance intensity accordingto the process of the present invention. The fragrance, glycol and/oramount of plasticizer are each selected to account for the residualamount of net plasticizer upon optimization of the amount of fragranceaccording to the process of the present invention.

Processing Techniques

Before any processing techniques are employed, an amount of plasticizeris added to the pre-melt cellulosic to prevent degradation upon heating.Fragrance, and other additives such as alkylene glycols or glycol ethersmay be added with the plasticizer, or more preferably, after an initialamount of plasticizer has already been added to the pre-melt cellulosic.In the preferred two-step process, the plasticizer is first added to thepre-melt cellulosic and, once the mixture is visibly dry (meaning theliquid plasticizer has absorbed into the interior of the cellulose esterpowder particle), the fragrance is then dispersed over the powder. Theplasticizer which has been already absorbed into the powder acts as areceptor to the fragrance and helps it migrate into the particles of thepre-melt cellulosic.

As described above, the plasticizer and fragrance—which also acts as aplasticizer—together form the “net plasticizer”. The introduction of afragrance into the cellulosic requires a mixing step such that thefragrance is sufficiently dispersed throughout the pre-melt cellulosic.The pre-melt cellulosic can then be processed into solid pellets bytechniques known to those of ordinary skill in the art, non-limitingexamples of which are described below:

(a) Single-Screw Compounding (SSC)—SSC requires a separate heating,agitation, and mixing step to combine a compatible pre-heated liquidplasticizer in appropriate proportions, possibly with colorants,stabilizers, and additives with the pre-melt cellulosic. Heat isrequired both for the powder and for the plasticizer to aid in itsabsorption into the interior of each powder particle. Constant agitationof the powder is required to ensure that both the heat being introducedand the additives are being uniformly distributed. The liquid additiveswill absorb into the powdered polymer, and any dry powder additives mustbe evenly dispersed throughout the blend of materials. The final mixedmaterials are then processed through a plastics extrusion melt process,which imparts to the materials sufficient heat and pressure toplasticate the polymer. The extrudate is then pushed from the extruderthrough a die into a multitude of strands. The strands are subsequentlycut into pellets, which can subsequently be processed through othersecondary melt processes into various end products.

(b) Twin-Screw Compounding (TSC)—TSC extruders offer the ability toeliminate the dry-mixing step necessary for SSC. While the same mixingsteps can be used prior to introduction of the entire mixture into atwin-screw extruder for plasticating and then pelletizing the materials,it is possible to introduce all of the components into various stages ofa twin-screw compounding extruder without prior mixing. As in SSC, thefragrance can be either added in combination with the plasticizer, or itcan be introduced in a second step.

(c) Solvent casting—Cellulose esters, including cellulose diacetate andcellulose triacetate are used as cellulosics in various embodiments ofthe present invention. Cellulose esters may be processed into thin filmsusing solvent casting techniques known to a person of ordinary skill inthe art. For example, the cellulose ester may be dissolved in a solventsuch as acetone or methylene chloride to prepare a viscous dope.Standard plasticizer may be added to the viscous dope and processed ontoa substrate, such as polished stainless steel or chrome. When thesolvent evaporates it leaves a remaining, preferably uniform, film ofplasticized cellulose ester film.

Upon control of concentration, pressure, temperatures, feed rates,evaporation rates, etc., solvent casting techniques can be used toprovide scented cellulosics for an end use application. This techniqueis conducive to fragranced cellulosic applications due to the relativelow processing temperatures, as compared to other techniques such asmelt-extrusion. For example, solvent casting techniques can be used inembodiments of the present invention to prepare scented cellulosics withoptimal fragrance intensity, and/or a scented cellulosic with analkylene glycol or alkylene glycol ether of the present invention.

(d) Secondary Melt-Processing—Once processed into solid pellet form, thefragranced cellulosics are then processed into an end-use application bymeans of a secondary melt-processing step. Non-limiting examples ofsecondary melt-processing steps include compression molding, injectionmolding, casting and extrusion. Secondary Melt-Processing Techniques aredescribed in Chapter XV of “Methods of Processing and Fabrication”,Handbook of Plastics, Ninth Printing (1943), which is herebyincorporated by reference in its entirety.

Determining Initial Fragrance Intensities and Fragrance Longevity

Fragrance intensities and fragrance longevity can be determined bypersons of ordinary skill in the art. For example, fragrance intensitiesof a sample of products can be rated on a scale by a panel ofindividuals trained to ascertain the intensity of the fragrancesubjectively perceived by the panel members. Preferably the test isperformed in a controlled environment devoid of smells that couldinfluence the results, and the panel is not informed of the contents ofthe samples to avoid bias. Further information regarding measuringfragrance intensities can be found, for example in ASTM Standard E544-99, “Standard Practices for Referencing Suprathreshold OdorIntensity; which is hereby incorporated by reference in its entirety.

Similarly, fragrance longevities can be determined by person's ofordinary skill in the art. For purposes of this application, fragrancelongevity can be defined as the period of time in which a compositionretains at least 50% of its initial fragrance. Alternatively, longevitycan be measured based on the period of time in which the compositionretains a perceivable fragrance. Again, the perception of fragrance ispreferably carried out by person's trained in art (e.g., “noses”) and ina fragrance-controlled environment.

End-Use Applications

Various end-use applications are possible and within the scope of thepresent application. While it is preferred that such end-useapplications for scented cellulosics have optimal fragrance intensity,including maximum fragrance intensities, and/or being processed with,and hence containing, a solvent system as described above, the end-useapplications discussed below can be prepared using any process toprepare scented cellulosic formulations.

In embodiments of the present invention, end uses prepared from thesolid pellets of the present invention have a structural form, forexample, flexible sheets, containers, and solid objects such as cellphone holsters or the outer casing for the cell phone itself.

Non-limiting examples of end-use applications include jewelry andpersonal accessories including, but not limited to, bangles, bracelets,necklaces, earrings, pendants, ankle bracelets, facial jewelry such asnose, lips and eyebrow rings and studs, headbands, belt buckles,buttons, barrettes, hair bands, hair clips, bobby pins, zippers, pocketprotectors, thimbles, rubber bands, including rubber bands used to bindhair, clothing stays & clasps, shoelace caps, bands for use withwristwatches and shoulder bags, holsters for cell phones, money clips,change holders, purses, wallets, sunglasses and eyeglasses cords,eyewear, such as frames for glasses, razor handles, hair accessories,hairbrush handles, toothbrushes handles, toothbrush holders, cases,computer mice, calculator cases, telephone headsets, packaging tape, andribbons.

Other examples of end-use applications include keychains, promotionalitems for fragrance companies to replace, for example, scent strips,packaging and/or containers for hand sanitizers and fragrance products,including perfume, cologne, and after shave, cellowrap, credit cards,gift cards, artificial flowers and plants, bottle caps, binder clips,automobile air fresheners, shower curtain rings, shower curtains,bathroom garbage cans, toothbrushes, headsets for phones, razor handles,splints for inclusion in first-aid kits, soap holders, sachets, hairaccessories, hangers, including clothes hangers, shoe horns, shoe trees,sunglasses, learning tools for kids, toys for kids (e.g. play kitchensets with scented pizza, corn) and replacements for scratch-and-sniffbooks, cigarette lighters, and inserts for greeting cards.

As non-limiting examples of interior and household accents, the processof present invention can be used to prepare pen holders, pen cases, soapdishes, table decorations, vases, desk ornaments, candle holders,decorative non-burning candles, clothespins for hanging laundry, napkin,toilet paper, and paper towel dispensers, television remote controlcasings, cases for clocks, picture frames, bathtub toys such as floatingducks, makeup and compact cases, lunch boxes, cutting boards, lampshades, telephones, refrigerator magnets, dish drains, letter holders,placemats, cases for personal products such as pill reminder cases,dental floss, and retainers, air fresheners, auto trim, drawer sachets,plates, cups, spoons, forks, other utensils involved in foodpreparation, pots for indoor plants, material for Venetian blinds, saltand pepper shakers, condiment holders, food storage devices, and garbagecans and lids. These products can also be prepared by other processesfor preparing scented cellulosics.

Point of purchase applications that can be prepared by the process ofthe present invention include, but are not limited to, packagingcomponents such as fragrance displays to replace spritzing, tubes,cellowrap, caps, trim, display components such as rails and trim,including promotional display advertisements directed to personal careproducts such as deodorants, mouthwash, and flavored pharmaceuticalproducts, including cough suppressants, sore throat lozenges or sprays,pain reducers, fever reducers, vitamins, antibiotics, and cold andinfluenza medications. Other end-use products include, containers withfragrances similar to the product contained within, mailing productsused to store and transport clothes, and security tags for stores.Another set of uses include devices and components used for transferringscent to clothing, such as hangers, shoe horns, shoe trees, sachets,clothing inlays, and protective wrap for products.

The process of the present invention can also be used to prepare, forexample, animal lures, animal toys, and insect repellents, such as mousetraps, rodent traps, roach “motels”, animal attractants, includingaccessories for hunters, animal repellants, including ornamental lawnfurniture or tomato or garden stakes that have fragrances that repeldeer and other wildlife, fishing lures, toys for household pets, such asgnawable artificial food or toys, fake play rodents such as a pretendmouse, collars, balls, frisbees, and other “fetchable” objects, scentedpoles to attract and capture insects, and artificial moth balls.

The following examples illustrate the present invention withoutlimitation.

Example 1

A series of formulations of fragranced cellulose acetate proprionatewith a proprietary pina colada fragrance and Dioctyl Adipate (DOA)having varying fragrance:plasticizer ratios were prepared as shownbelow:

Net Wt % Wt % Plasticizer - Fragrance:Plasticizer Sample FragrancePlasticizer wt % Ratio 1 5 5 10 1 2 6 4 10 1.5 3 7 3 10 2.33 4 8 2 10 4

Ten individuals were asked to rank the samples on the basis of strengthof scent level. The identify of the samples were not identified to thepanel.

Sample 1, containing a fragrance:plasticizer ratio of 1 was judged byall 10 panelist to have the strongest fragrance. Sample 4, whichcontains four-fold increase in fragrance:plasticizer ratio, was judgedby all 10 panelist to be the weakest fragrance. All four samples did notexhibit processing problems due to insufficient plasticizer amount.

Example 2

The following pre-melt cellulosic compositions were prepared:

Amount Amount of Type of of Net Traditional Traditional Amount of Amountof Amount of Plasticizer Plasticizer Plasticizer Type of CellulosicFragrance Hexylene (wt %) (wt %) (wt %) Cellulosic (wt %) (wt %) Glycol  33%  8.10% DEP CA 67.00% 19.30%   5.60%   33%   10% DEP CA 67.00% 15%  8%   33%   10% DEP CA 67.00% 15%   8%   33%    8% DEP CA 67.00% 19%  6%   33%   13% DEP CA 67.00% 20%   0%   33%   10% DEP CA 67.00% 17%  6%   33%   15% DEP CA 67.00% 18%   0%   27%  14.2% DEP CA 73.30% 10% 2.4%   33%   10% DEP CA 67.00% 15%   8% 33.70%    9% DEP CA 66.30% 18%  6% 29.40%    8% DEP CA 70.60% 15%   6%   35%   11% DEP CA 65.00% 18%  6%   33%   15% DEP CA 67.00% 18%   0%   33%   10% DEP CA 67.00% 15%  8%   33%   10% DEP CA 67.00% 15%   8%   33%   10% DEP CA 67.00% 15%  8% 35.50%   12% TRI CA 64.50% 18%   6% 35.50%   18% TRI CA 64.50% 18%  0% 33.70%    9% DOA CAP 66.30% 18%   6% 29.40%    8% DOA CAP 70.60%15%   6% 32.50% 16.50% DEP CA 67.50% 10%   6%   41%   13% TRI CA 59.00%22%   6%   36% 11.30% DEP CA 64.00% 19%   6% 33.30% 11.40% DEP CA 66.70%18.90%     3%   38% 13.20% DEP CA 62.00% 19% 5.80%   36% 14.50% TRI CA64.00% 15% 6.80% 35.30% 13.20% DEP CA 64.70% 16.70%   5.40%   36% 14.70%DEP CA 64.50% 15% 5.90%   14%  3.90% DOA CAP 86.00% 10% 0.00% 33.50%16.40% DEP CA 66.50% 10% 7.10% 39.50% 16.60% DEP CA 60.50% 18.10%  6.40% 33.60% 16.60% DEP CA 66.40% 10%   7% 38.60% 14.90% DEP CA 61.40%23.70%     0% 38.60% 14.90% DEP CA 61.40% 19.10%   4.70% 38.60% 14.90%DEP CA 61.40% 23.70%     0% 38.60% 14.90% DEP CA 61.40% 19.10%   4.70%  38%   16% DEP CA 62.00% 17%   5% 37.70% 17.90% DEP CA 62.30% 19.80%    0% 38.00% 15.00% DEP CA 62.00% 17%   6% 35.30% 13.20% DEP CA 64.70%16.70%   5.40% 39.50% 14.90% DEP CA 60.50% 18.10%   6.40% 29.50%  8.5%DEP CA 70.50% 15%   6%   37%  15.5% DEP CA 62.60% 17%   5%   37%  15.5%DEP CA 62.60% 17%   5%   37%  15.5% DEP CA 62.60% 17%   5% 33.50% 16.40%DEP CA 66.50% 10% 7.10% 37.40% 15.50% DEP CA 62.60% 17%   5%   14%  9.5%DOA CAP 86.00% 4.4%   0%   34%   16% DEP CA 66.00% 12.50%   5.50%   34%  16% DEP CA 66.00% 12.50%   5.50% 33.50% 16.40% DEP CA 66.50% 10% 7.10%39.50% 16.88% DEP CA 60.50% 18.10%   6.40% 33.30% 18.20% DEP CA 66.70%10% 5.10%   14%  9.50% DOA CAP 86.00% 4.40%     0%   34%   16% DEP CA66.00% 12.50%   5.50%   34%   16% DEP CA 66.00% 12.50%   5.50% 38.50%15.40% DEP CA 61.50% 18% 5.10% 38.50% 15.40% DEP CA 61.50% 18% 5.10%38.50% 15.40% DEP CA 61.50% 18% 5.10% 35.50% 17.50% DEP CA 64.50%12.50%   5.50% 35.50% 17.50% DEP CA 64.50% 12.50%   5.50% 35.50% 17.50%DEP CA 64.50% 12.50%   5.50% 35.50% 17.50% DEP CA 64.50% 12.50%   5.50%35.50%   23% DEP CA 64.50% 12.50%   0.00% 18.30% 10.00% DOA CAP 81.70%10%   0% 32.90% 20.30% DEP CA 67.10% 2.50%   10.10%  32.90% 20.30% DEPCA 67.10% 2.50%   10.10%    34%   16% DEP CA 66.00% 12.50%   5.50%   34%  16% DEP CA 66.00% 12.50%   5.50% 33.50% 16.40% DEP CA 66.50% 10% 7.10%  37%   16% DEP CA 63.00% 15%   6% 32.90%   23% DEP CA 67.10% 10%   0%32.90%   23% DEP CA 67.10% 10%   0% 14.50%  9.50% DOA CAP 85.50%  5%  0%   19%    7% DOA CAP 81.00% 10%   2% 14.50% 11.50% DOA CAP 85.50% 3%   0% 25.30%  7.30% DOA CAP 74.70% 15%   3%   14%  9.50% DOA CAP86.00% 4.40%     0% 38.50% 15.40% DEP CA 61.50% 18% 5.10% 38.50% 15.40%DEP CA 61.50% 18% 5.10% 32.50% 16.90% DEP CA 67.50% 10% 5.60% 32.50%16.90% DEP CA 67.50% 10% 5.60% 35.50% 17.50% DEP CA 64.50% 12.50%  5.50% 29.50%  8.5% DEP CA 70.50% 15%  6.0% 34.00%  10.0% DEP CA 66.00%14%   10% 29.50%  14.5% DEP CA 70.50% 15%   0% 34.00%  20.0% DEP CA66.00% 14%   0% 20.70%  8.80% DOA CAP 79.30% 11%   1%   24%  8.5% DOACAP 76.50% 15%   0% 36.30% 16.00% DEP CA 63.70% 15% 5.30% 32.70% 20.40%DEP CA 67.30% 2.10%   10.10%  38.50% 15.40% DEP CA 61.50% 18% 5.10%38.50% 15.40% DEP CA 61.50% 18% 5.10% 36.30% 16.00% DEP CA 63.70% 15%5.30%

Types of traditional plasticizer used include diethyl phthalate (DEP);triacetin (TRI); and dioctyl adipate (DOA). Types of cellulosics includecellulose acetate (CA) and cellulose acetate propionate (CAP).

The above pre-melt formulations were processed via either a laboratoryroll-mill, and/or using single-screw melt-extrusion compounding.Packaging components, point-of-purchase display components, thin filmsfor packaging, jewelry; air fresheners; and promotional items wereprepared.

Example 3

A 0.003″ thick fragranced film of cellulose acetate is prepared for apackaging end use application. As a “hard” melt flow is desired, thetarget wt % net plasticizer for the pre-melt cellulosic is 27%. Thedesired fragrance is inherently a relatively strong fragrance, and a“medium” fragrance intensity on the film is desired. An initialfragrance target of 10% is chosen. A hexylene glycol level of 2.5% ischosen to allow a residual level of 14.5% traditional plasticizer in theformulation.

Example 4

A molded decorative desk ornaments, approximately 2 inches thickutilizing cellulose acetate is prepared. A “soft” melt flow is desired.The target wt % net plasticizer for this application is 38%. The desiredfragrance is a subtle fragrance, and a strong fragrance intensity isdesired. A fragrance target of 16% is chosen. A Hexylene Glycol level of8% is chosen to allow a residual traditional plasticizer level of 14% inthe formulation.

Example 5

Pre-melt compositions of cellulose acetate, diethyl phthalateplasticizer, proprietary fruit punch fragrance and hexylene glycol inthe amounts shown below were processed into pellets and their fragranceintensity was rated by an observer:

wt % wt % Traditional wt % Fragrance:Plasticizer hexylene FragranceFragrance Plasticizer Fragrance Ratio glycol Intensity Longevity 8.8 192.16 6 Very Weak 15 days 11.5 19 1.65 6 Strong 60+ days   11.5 19 1.65 3Medium 45 days 13 19 1.46 6 Strong 60+ days   13 20 1.54 0 Strong 60days 16 17 1.06 0 Medium/Strong 40 days 18 15 0.83 0 Medium 30 days

It is noted that initial fragrance intensity is related to fragrancelongevity, i.e., increased initial fragrance intensities yieldlonger-lasting fragrances and samples with lower initial fragranceintensities yield samples in which the fragrance does not last as long.

The above mentioned patents, patent applications, patent publications,test methods, and publications are hereby incorporated by reference intheir entirety.

Many variations of the present invention will suggest themselves tothose skilled in the art in light of the above detailed description. Allsuch obvious variations are within the fully intended scope of theinvention.

1-20. (canceled)
 20. A pre-melt composition for a scented cellulosiccomprising: a pre-melt cellulosic selected from the group consisting ofcellulose acetates and cellulose acetate esters; a plasticizer; afragrance component; and a solvent system that comprises a componentthat has both a non-polar and polar character, wherein the solvent ispresent in an amount between about 0.5% to about 20% by weight of thecomposition.
 21. The pre-melt composition for a scented cellulosic ofclaim 20, wherein the solvent system comprises a component that issoluble in both an alcohol and benzene.
 22. The pre-melt composition fora scented cellulosic of claim 20, wherein the solvent system includes aglycol or glycol ether.
 23. The pre-melt composition for a scentedcellulosic of claim 20, wherein the solvent system has nonioniccharacteristics allowing the solvent system to be miscible in theplasticizer which is nonpolar in nature and the solvent system hasavailable functional groups allowing for hydrogen-bonding between theplasticizer and the fragrance which is more polar in nature compared tothe solvent.
 24. The pre-melt composition for a scented cellulosic ofclaim 23, wherein the functional groups comprise hydroxyl groups. 25.The pre-melt composition for a scented cellulosic of claim 20, whereinthe solvent system is present in an amount that is effective tofacilitate migration of the fragrance through the cellulosic.
 26. Ascented cellulosic composition comprising: a pre-melt cellulosicselected from the group consisting of cellulose acetates and celluloseacetate esters; a plasticizer; a fragrance component; and a glycol orglycol ether; wherein the cellulosic is at least about 40% by weight ofthe total weight of the composition.
 27. The composition of claim 26,wherein the glycol is a C₃-C₁₂ substituted or unsubstituted alkyleneglycol or a poly(C₃-C₁₂ substituted or unsubstituted alkylene glycol).28. The composition of claim 26, wherein the glycol is a C₅-C₁₀substituted or unsubstituted alkylene glycol or a poly(C₅-C₁₀substituted or unsubstituted alkylene glycol).
 29. The composition ofclaim 26, wherein the glycol is a C₅-C₇ substituted or unsubstitutedalkylene glycol or a poly(C₅-C₇ substituted or unsubstituted alkyleneglycol).
 30. The composition of claim 26, wherein the glycol is hexyleneglycol.
 31. The composition of claim 26, wherein the plasticizer isselected from dibutyl phalate, diethyl phthalate, dimethyl phthalate,triacetin, diethylhexyl-phthalate, and dioctyl phthalate.
 32. Thecomposition of claim 26, wherein the glycol ether is an alkyl ether ofalkylene glycol or poly(alkylene glycol).
 33. The composition of claim26, wherein the glycol ether is a C₄-C₇ mono or poly alkyl ether of analkylene glycol or polyalkylene glycol.
 34. The composition of claim 26,wherein the glycol ether is a butyl ether of an alkylene glycol or apolyalkylene glycol.
 35. The composition of claim 34, wherein thealkylene glycol is diethylene glycol.
 36. The composition of claim 26,wherein the glycol ether is butyl carbitol.
 37. The composition of claim26, wherein the glycol ether is selected from propylene glycol monoethylether, dipropylene glycol monoethyl ether, and tripropylene glycolmonoethyl ether.
 38. The composition of claim 37, wherein the glycolether is dipropylene glycol monoethyl ether.
 39. A pre-melt compositionfor a scented cellulosic comprising: a pre-melt cellulosic selected fromthe group consisting of cellulose acetates and cellulose acetate esters;a plasticizer; a fragrance component; and a solvent system thatcomprises a component that has both a non-polar and polar character,wherein the solvent system has nonionic characteristics allowing thesolvent system to be miscible in the plasticizer which is nonpolar innature and the solvent system has available functional groups allowingfor hydrogen-bonding between the plasticizer and the fragrance which ismore polar in nature compared to the solvent, wherein the functionalgroups comprise hydroxyl groups, the solvent system being present in anamount that is effective to facilitate migration of the fragrancethrough the cellulosic.